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Genomic instability in mouse Burkitt lymphoma is dominated by illegitimate genetic recombinations, not point mutations
Journal article   Peer reviewed

Genomic instability in mouse Burkitt lymphoma is dominated by illegitimate genetic recombinations, not point mutations

Lynne D Rockwood, Ted A Torrey, Joong Su Kim, Allen E Coleman, Alexander L Kovalchuk, Shao Xiang, Thomas Ried, Herbert C Morse III and Siegfried Janz
Oncogene, Vol.21(47), pp.7235-7240
10/17/2002
DOI: 10.1038/sj.onc.1205697
PMID: 12370814

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Abstract

lambda-MYC-induced mouse Burkitt lymphoma (BL) harboring the shuttle vector pUR288, which includes a lacZ reporter gene to study mutagenesis, was employed to assess genomic instability associated with MYC deregulation. The frequency of lacZ mutations in lymphomas was elevated only 1.75-fold above that in normal tissue, indicating that mouse BL does not exhibit a phenotype of hypermutability. However, the nature of lacZ mutations was strikingly different in normal tissues and lymphomas. While point mutations comprised approximately 75% of the mutations found in normal tissues, apparent translocations, deletions and inversions constituted the majority of mutations ( approximately 65%) in lymphomas. Genomic instability in mouse BL thus seems characterized by a preponderance of illegitimate genetic rearrangements in the context of near-background mutant frequencies. SKY analyses of cell lines from primary BL tumors revealed substantial changes in chromosomal structure, confirming the lacZ studies. Bi-allelic deletions of the tumor suppressor p16(Ink4a) were detected in six out of 16 cell lines, illustrating cellular selection of advantageous mutations. Together, these approaches indicate that MYC may contribute to lymphomagenesis through the dominant mutator effect of inducing chromosomal instability. The results further suggest that a phenotype of hypermutability (elevated mutant frequency) may not always be required for oncogenesis to occur.
Genes, Immunoglobulin Genes, myc - physiology Cell Line Point Mutation Animals Recombination, Genetic Burkitt Lymphoma - genetics Mice, Transgenic Mice Genes, p16 Genes, Reporter Lac Operon

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